Citation and License

Abstract

Background

Most individuals exposed to a traumatic event do not develop post-traumatic stress
disorder (PTSD), although many individuals may experience sub-clinical levels of post-traumatic
stress symptoms (PTSS). There are notable individual differences in the presence and
severity of PTSS among individuals who report seemingly comparable traumatic events.
Individual differences in PTSS following exposure to traumatic events could be influenced
by pre-trauma vulnerabilities for developing PTSS/PTSD.

Methods

Pre-trauma psychological, psychophysiological and personality variables were prospectively
assessed for their predictive relationships with post-traumatic stress symptoms (PTSS).
Police and firefighter trainees were tested at the start of their professional training
(i.e., pre-trauma; n = 211) and again several months after exposure to a potentially
traumatic event (i.e., post-trauma, n = 99). Pre-trauma assessments included diagnostic
interviews, psychological and personality measures and two psychophysiological assessment
procedures. The psychophysiological assessments measured psychophysiologic reactivity
to loud tones and the acquisition and extinction of a conditioned fear response. Post-trauma
assessment included a measure of psychophysiologic reactivity during recollection
of the traumatic event using a script-driven imagery task.

Conclusion

The current study contributes to a very limited literature reporting results from
truly prospective examinations of pre-trauma physiologic, psychologic, and demographic predictors of
PTSS. Findings that combinations of lower estimated IQ, greater depression symptoms,
a larger differential corrugator EMG response during extinction and larger SC responses
to loud tones significantly predicted higher PTSS suggests that the process(es) underlying
these traits contribute to the pathogenesis of subjective and physiological PTSS.
Due to the low levels of PTSS severity and relatively restricted ranges of outcome
scores due to the healthy nature of the participants, results may underestimate actual
predictive relationships.